Dr. Hooper carefully details the “opportunities and challenges” associated with the expanding use of fluoroquinolones (1). However, although he warns that indiscriminate use of these antimicrobial agents, particularly for the treatment of respiratory infections, may lead to the emergence of resistance in Streptococcus pneumoniae, he speculates that such an event may be slow to occur. We report a clinical isolate of S. pneumoniae resistant to both levofloxacin and trovafloxacin, two newer-generation fluoroquinolones recommended for treatment of community-acquired pneumonia (2).

A 63-year-old man was hospitalized with pneumonia and was empirically treated with levofloxacin, an antimicrobial agent he had been prescribed days earlier for treatment of bronchitis. During hospitalization, his condition did not improve; S. pneumoniae grown from the patient's sputum was resistant to both levofloxacin (minimum inhibitory concentration [MIC] >32 µg/mL) and trovafloxacin (MIC, 4 µg/mL) and showed intermediate resistance to penicillin (MIC, 1 µg/mL). The patient improved after treatment with ceftriaxone, to which the isolate was susceptible (MIC, 0.5 µg/mL). Antimicrobial susceptibilities were determined by the Etest method (3).